Hi,
y= -[x-10]^2+75 ||Parabola opening downward, V(10,75)maximum point
max height the diver is above the water = 75m
the vertex form of a Parabola opening up(a>0) or down(a<0),
where(h,k) is the vertex and x = h is the Line of Symmetry
The standard form is, where the focus is (h,k + p)